It is known to mix sodium chlorite and mineral acid solutions together in a concentrated form. The mixing occurs within a few minutes and the object is to maximize the production of chlorine dioxide from the reactants. This concentrate is then diluted with water down to application levels of parts per million for use to eliminate spoilage and pathogenic organisms on food items. An object of the present invention is to provide a method and apparatus for deliberately mixing the sodium chlorite and acid solutions in a water stream in such a way that the chlorine dioxide forms slowly over a period of hours and even days.
Known systems for producing and/or using chlorine dioxide are disclosed in the following United States patents: U.S. Pat. No. 4,013,761, granted Mar. 22, 1977 to William J. Ward and Kenneth E. Gasper; U.S. Pat. No. 4,534,952, granted Aug. 13, 1985, to W. Howard Rapson and Maurice C. J. Fredette; U.S. Pat. No. 4,925,645, granted May 15, 1990, to James A. Mason; U.S. Pat. No. 5,009,875, granted Apr. 23, 1991, to Joseph M. Kelley, Donald C. Kucher and George Mayurnik; U.S. Pat. No. 5,618,440, granted Apr. 8, 1997, to James A. Mason; U.S. Pat. No. 5,799,833, granted Sep. 1, 1998, to Thomas S. Green and Eric G. Hilston; U.S. Pat. No. 5,863,584, granted Jan. 26, 1999, to Thomas Iverson Jr., Joyce Prindle and Robert E. Keith; U.S. Pat. No. 6,004,604, granted Dec. 21, 1999 to Thomas Iverson Jr., Joyce Prindle and Robert E. Keith; and U.S. Pat. No. 6,120,731, granted Sep. 19, 2000, to Robert D. Kross and Kere Kemp.